# A Rare Case when “That” is Preceded by “Comma” on GMAT

This short video explains a rare case when "that" is preceded by a comma. A useful concept for the GMAT sentence correction questions.

## A Rare Case when "That" is Preceded by "Comma"

On the GMAT, the word "that" will not typically follow a comma; however, there are rare cases where it does. When the word "that" is preceded by a comma, the related phrase does not modify the sentence in the same way that it would if a word such as "which" or "who" were used. In this short article, we will cover the rare case where the word "that" is preceded by a comma; while this case is not one that you will encounter often on the GMAT, understanding this concept will be useful on the GMAT sentence correction questions.

In the case when the word "that" is preceded by a comma, "that" does not refer to the noun immediately before the comma; rather, it refers to the noun/noun phrase that is before the earlier comma. Let us illustrate this concept through the following example:

Example 1 - While flying at night, bats use echolocation, a special sonar system used by toothed whales as well as dolphins, that involves the use of sound waves and echoes for determining where objects are in space.

As you can see, in this sentence, the word "that" follows a comma that follows the noun "dolphins". Unlike other such sentence constructions, here, "that" will not refer to the noun that is immediately before the comma, "dolphins", it will refer to the noun that follows the previous comma that is "echolocation". This concept can be best understood by taking the meaning of the sentence into account. The core meaning of the sentence is that bat use echolocation that involves the use of sound waves and echoes for determining where objects are in space while flying at night. There is also additional information within the two commas that modifies the noun "echolocation", to explain that it is a special sonar system used by toothed whales as well as dolphins. If the word "that" referred to "dolphins", the meaning of the sentence would be that dolphins involve the use of sound waves and echoes for determining where objects are in space; obviously, this changes the core meaning of the sentence completely. Thus, the sentence can only be correct if the word "that" refers to "echolocation".

This article has deliberately been kept brief; for a more elaborate explanation, please refer to Experts' Global's Stage One Sentence Correction videos.